feat: add agent decorators for configuration-as-code

README.md

@@ -10,6 +10,7 @@ The Python SDK offers a clean, type-safe API following Python best practices whi
 
 ### Key Features
 
+- **Agent Decorators**
 - **AI Core Integration**
 - **Audit Log Service**
 - **Destination Service**
@@ -58,6 +59,7 @@ The SDK automatically resolves configuration from multiple sources with the foll
 
 Each module has comprehensive usage guides:
 
+- [Agent Decorators](src/sap_cloud_sdk/agent_decorators/user-guide.md)
 - [AuditLog](src/sap_cloud_sdk/core/auditlog/user-guide.md)
 - [Destination](src/sap_cloud_sdk/destination/user-guide.md)
 - [DMS](src/sap_cloud_sdk/dms/user-guide.md)

src/sap_cloud_sdk/agent_decorators/__init__.py

@@ -0,0 +1,39 @@
+"""SAP Cloud SDK for Python - Agent Decorators module.
+
+Decorator-based configuration-as-code for SAP AI agents. Developers
+annotate functions with decorators to expose configuration fields
+(prompts, models, settings) to a low-code UI.
+
+Usage:
+    from sap_cloud_sdk.agent_decorators import (
+        prompt_section,
+        agent_config,
+        agent_model,
+    )
+
+    @prompt_section(
+        key="prompts.system",
+        label="System Prompt",
+        description="Main system prompt for the agent",
+    )
+    def system_prompt() -> str:
+        return "You are a helpful assistant."
+"""
+
+from sap_cloud_sdk.agent_decorators.decorators import (
+    agent_config,
+    agent_model,
+    prompt_section,
+)
+from sap_cloud_sdk.agent_decorators.exceptions import (
+    AgentDecoratorError,
+)
+
+__all__ = [
+    # Decorators
+    "prompt_section",
+    "agent_config",
+    "agent_model",
+    # Exceptions
+    "AgentDecoratorError",
+]

src/sap_cloud_sdk/agent_decorators/decorators.py

@@ -0,0 +1,138 @@
+"""Decorator functions for exposing agent configuration fields.
+
+Each decorator is a marker — it annotates a zero-argument function
+whose return value is the coded default for a configuration field.
+External tooling discovers these markers in source text and extracts
+their arguments and return values.
+
+At decoration time only the *key* is validated; the function is
+returned unchanged.
+"""
+
+from typing import Any, Callable, Optional
+
+from .exceptions import AgentDecoratorError
+
+
+def _validate_key(key: str) -> None:
+    """Validate a decorator key.
+
+    Raises:
+        AgentDecoratorError: If the key is empty or whitespace-only.
+    """
+    if not key or not key.strip():
+        raise AgentDecoratorError(
+            f"Decorator key must be a non-empty string, got {key!r}"
+        )
+
+
+def prompt_section(
+    key: str,
+    label: str,
+    description: str,
+    validation: Optional[dict[str, Any]] = None,
+) -> Callable:
+    """Expose a prompt section for editing.
+
+    Args:
+        key: Unique identifier for this prompt (e.g. ``"prompts.system"``).
+        label: Human-readable label shown in the UI.
+        description: Help text explaining what this prompt does.
+        validation: Optional validation rules as a dict
+            (e.g. ``{"format": "text", "max_length": 500}``).
+
+    Returns:
+        A decorator that validates the key and returns the function unchanged.
+
+    Raises:
+        AgentDecoratorError: If the key is empty or whitespace-only.
+
+    Example::
+
+        @prompt_section(
+            key="prompts.identity",
+            label="Agent Identity",
+            description="Core identity and role definition",
+            validation={"format": "text", "max_length": 500},
+        )
+        def get_identity_prompt() -> str:
+            return "You are an expert assistant..."
+    """
+    _validate_key(key)
+
+    def decorator(fn: Callable[[], str]) -> Callable[[], str]:
+        return fn
+
+    return decorator
+
+
+def agent_config(
+    key: str,
+    label: str,
+    description: str,
+) -> Callable:
+    """Expose an agent configuration value for editing.
+
+    Args:
+        key: Unique identifier (e.g. ``"config.temperature"``).
+        label: Human-readable label.
+        description: Help text.
+
+    Returns:
+        A decorator that validates the key and returns the function unchanged.
+
+    Raises:
+        AgentDecoratorError: If the key is empty or whitespace-only.
+
+    Example::
+
+        @agent_config(
+            key="config.temperature",
+            label="Temperature",
+            description="The temperature setting for the language model",
+        )
+        def get_temperature() -> float:
+            return 0.7
+    """
+    _validate_key(key)
+
+    def decorator(fn: Callable) -> Callable:
+        return fn
+
+    return decorator
+
+
+def agent_model(
+    key: str,
+    label: str,
+    description: str = "",
+) -> Callable:
+    """Expose an agent model selection for editing.
+
+    Args:
+        key: Unique identifier (e.g. ``"config.model"``).
+        label: Human-readable label.
+        description: Help text (optional).
+
+    Returns:
+        A decorator that validates the key and returns the function unchanged.
+
+    Raises:
+        AgentDecoratorError: If the key is empty or whitespace-only.
+
+    Example::
+
+        @agent_model(
+            key="config.model",
+            label="LLM Model",
+            description="The language model powering this agent",
+        )
+        def get_model_name() -> str:
+            return "sap/gpt-4o"
+    """
+    _validate_key(key)
+
+    def decorator(fn: Callable) -> Callable:
+        return fn
+
+    return decorator

src/sap_cloud_sdk/agent_decorators/exceptions.py

@@ -0,0 +1,7 @@
+"""Custom exceptions for SAP Agent Decorators."""
+
+
+class AgentDecoratorError(Exception):
+    """Base exception for agent decorator operations."""
+
+    pass

src/sap_cloud_sdk/agent_decorators/user-guide.md

@@ -0,0 +1,102 @@
+# Agent Decorators User Guide
+
+This module provides a decorator-based configuration-as-code system for SAP AI agents. Developers annotate functions with decorators to expose configuration fields — prompts, model selections, and agent settings — to a low-code UI. External tooling discovers these markers in source text and extracts their arguments and return values.
+
+## Installation
+
+The agent decorators module is part of the Cloud SDK for Python and is automatically available when the SDK is installed.
+
+## Import
+
+```python
+from sap_cloud_sdk.agent_decorators import (
+    prompt_section,
+    agent_config,
+    agent_model,
+)
+```
+
+## Quick Start
+
+```python
+from sap_cloud_sdk.agent_decorators import prompt_section, agent_model
+
+# Define a prompt with a coded default
+@prompt_section(
+    key="prompts.system",
+    label="System Prompt",
+    description="Main system prompt for the agent",
+)
+def system_prompt() -> str:
+    return "You are a helpful assistant."
+
+# Define the model selection
+@agent_model(key="config.model", label="LLM Model")
+def model_name() -> str:
+    return "gpt-4"
+```
+
+## Decorators
+
+### @prompt_section
+
+Expose a prompt section for editing.
+
+```python
+from sap_cloud_sdk.agent_decorators import prompt_section
+
+@prompt_section(
+    key="prompts.identity",
+    label="Agent Identity",
+    description="Core identity and role definition",
+    validation={"format": "text", "max_length": 500},
+)
+def identity_prompt() -> str:
+    return "You are an expert assistant specializing in SAP systems."
+```
+
+### @agent_config
+
+Expose a configuration value for editing.
+
+```python
+from sap_cloud_sdk.agent_decorators import agent_config
+
+@agent_config(
+    key="config.temperature",
+    label="Temperature",
+    description="Controls randomness (0.0 = deterministic, 1.0 = creative)",
+)
+def temperature() -> float:
+    return 0.7
+```
+
+### @agent_model
+
+Expose a model selection. The `description` parameter is optional.
+
+```python
+from sap_cloud_sdk.agent_decorators import agent_model
+
+@agent_model(
+    key="config.model",
+    label="Default Model",
+    description="The LLM model to use",
+)
+def default_model() -> str:
+    return "gpt-4"
+```
+
+## Error Handling
+
+```python
+from sap_cloud_sdk.agent_decorators.exceptions import AgentDecoratorError
+
+try:
+    @prompt_section(key="", label="L", description="D")
+    def bad():
+        return ""
+except AgentDecoratorError as e:
+    # Raised when decorator arguments are invalid (e.g. empty key)
+    print(f"Decorator error: {e}")
+```